At character creation , players distribute the following set of values between the six abilities: 16, 15, 13, 12, 9, 8. Each ability is useful for one of the Basic Moves . Each playbook tends to rely heavily on 1-2 abilities for class moves as well.
Strength measures muscle and physical power.
Dexterity measures agility, reflexes and balance.
Constitution represents your character’s health and stamina.
Intelligence determines how well your character learns and reasons.
Wisdom describes a character’s willpower, common sense, awareness, and intuition.
Charisma measures a character’s personality, personal magnetism, ability to lead, and appearance.
see good forum discussion on what ability scores vs. ability modifiers are used for.